Interpreting EPR data involves analyzing the spectra to extract relevant parameters such as g-values, hyperfine coupling constants, and line shapes. These parameters are compared with known standards or theoretical models to deduce information about the electronic and geometric structure of the catalytic species. Advanced techniques like ENDOR (Electron Nuclear Double Resonance) and ESEEM (Electron Spin Echo Envelope Modulation) can provide additional details and help in the comprehensive analysis of complex systems.